Wi-Fi Access Point Powered by Hostapd Sends Malformed Packets to 65th Client

Daniel Miess DMiess at sierrawireless.com
Wed Jun 20 08:40:19 PDT 2018


Hi Ben,

Thanks for looking into this. I'll attempt to reproduce this issue on my host PC and get back to you with the results.

Thanks,
Daniel

-----Original Message-----
From: Ben Greear <greearb at candelatech.com> 
Sent: Tuesday, June 19, 2018 3:42 PM
To: Daniel Miess <DMiess at sierrawireless.com>; hostap at lists.infradead.org
Subject: Re: Wi-Fi Access Point Powered by Hostapd Sends Malformed Packets to 65th Client

On 06/19/2018 03:32 PM, Ben Greear wrote:
> On 06/19/2018 01:59 PM, Daniel Miess wrote:
>> Hi Ben,
>>
>> The Wi-Fi module in question is using a QCA9880 chipset. The driver 
>> is Ath10k on the 3.14.28 kernel with some backports. The firmware is v10.1 of the Candela Tech Ath10k firmware.
>
> I would suggest trying to reproduce this with a recent stock kernel (4.16 or 4.17), stock QCA firmware, and stock hostapd.
>
> You can do this in a PC with the 9880 NIC in it, so no special 
> backports or other board-specific stuff will be needed.
>
> If the problem persists in stock code, then it would be worth looking 
> more closely at the hostapd (and since you would be using stock code 
> and normal hardware, others could probably reproduce the same problem for debugging).
>
> If the problem does not persist with stock code, then you can try 
> introducing the ath10k-ct driver and/or firmware in a controlled manner to see if they are at fault.

And, FYI, we just ran a test with the 9880 chip on our 4.13.16+ kernel, with our ath10k-ct
10.1 firmware, and we can get 126 stations associated with no problems.  Our hostapd includes the patches you bisected to.

We were using our own wifi-station emulator to be the stations, and our hardware is different and so forth, so there could still be problems that we do not see for whatever reason.

Thanks,
Ben


>
> Thanks,
> Ben
>
>
>>
>> Thanks,
>> Daniel
>>
>> -----Original Message-----
>> From: Ben Greear <greearb at candelatech.com>
>> Sent: Tuesday, June 19, 2018 9:34 AM
>> To: Daniel Miess <DMiess at sierrawireless.com>; 
>> hostap at lists.infradead.org
>> Subject: Re: Wi-Fi Access Point Powered by Hostapd Sends Malformed 
>> Packets to 65th Client
>>
>> On 06/19/2018 08:44 AM, Daniel Miess wrote:
>>> Hello Everyone,
>>>
>>> I am debugging an issue I have with an access point powered by 
>>> Hostapd. Hostapd was built with the default defconfig configuration 
>>> and is using a Wi-Fi card which uses Ath10k drivers. I am running a 
>>> test where I attempt to connect 128 clients to an access point 
>>> running on the card in rapid succession. I am able to connect 64 
>>> clients to the card in about 6 or 7 seconds but once the 65th client is reached the process stalls. Responses from the access point to authentication requests from this client are malformed, being sent out with incorrect frame check sequences. I do not encounter this issue when running hostapd 2.5 but observe it with 100% reproducibility on version 2.6 as well as the latest git master branch. By bisecting I was able to narrow down my issue to a pair of commits: dc55b6b & bb598c3. These commits are seeking to "Add support for full station state operations".
>>>
>>> Is there someone familiar with the work done in these check-ins who 
>>> can comment on why I might be seeing this behavior and what I might be able to do to work around it?
>>
>> ath10k behavior is significantly impacted by what firmware, driver, 
>> and chipset it is using, so please let us know what versions of those components you are using.
>>
>> Thanks,
>> Ben
>>
>>>
>>> Thanks,
>>> Daniel
>>>
>>>
>>> _______________________________________________
>>> Hostap mailing list
>>> Hostap at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/hostap
>>>
>>
>>
>> --
>> Ben Greear <greearb at candelatech.com>
>> Candela Technologies Inc  http://www.candelatech.com
>>
>
>


--
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com




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